'PropertySet.PropertyExists' in Siebel eScript gives error

Hi Gurus,

We have business Service code which uses the method: 'PropertySet.PropertyExists'

sample code:

var sBAItems = TheApplication().NewPropertSet();

//Query on Line Items BC and get its billing account id

sBillingAccountId = GetFieldValue("Billing Account Id");

sBillingStatus = GetFieldValue("Billing Account Sub Status");

if(!sBAItems.PropertyExists(sBillingAccountId))

{

sOrder = TheApplication().InvokeMethod("LOV_Type", "sBillingStatus ");

sBAItems.SetProperty(sBillingAccountId, sOrder );

}

if(!sBAItems.PropertyExists(sBillingAccountId)) - gives an error stating: SBL-SCR-00147: The #1 argument passed to method 'PropertySet.PropertyExists' was invalid. A String was expected.

Could you please suggest on fixing it; it was working piece for quite long time and suddenly gives this error.

Thanks & Regards,